Urgent questions for airtickets, Thanks!I am PR here and applied for my wife a social visit pass before (30 days stay). She is going to come to here from chengdu the end of this month and thus buy a one way air ticket (from chengdu to singapore) rather than two ways as she will extend her social visit pass after arrival and stay here for a longer time (waiting for PR approval). But I heard in some cases that return air ticket should be presented at the checkpoint in both china and singapore customs especially in china. for this kindly ask for your experience about it? is it compulsory for return air tickets to be shown? Thanks a lot in advance!